Ice cream machine including a baffled evaporator

ABSTRACT

An ice cream machine for cooling liquid ice cream into frozen ice cream includes an evaporator with baffles. The evaporator can be a flooded evaporator or evaporator having an auxiliary tank or section of the evaporator that can ensure that a cooling chamber is surrounded by liquid refrigerant during normal operation.

CROSS REFERENCE TO RELATED PATENT APPLICATIONS

[0001] The present application is a continuation-in-part of U.S. patentapplication Ser. No. 09/639,062 filed Aug. 15, 2000 entitled, “BatchProcess and Apparatus Optimized to Efficiently and Evenly Freeze IceCream”, which is a continuation-in-part of U.S. patent application Ser.No. 09/234,970, filed by Ross on Jan. 21, 1999, now U.S. Pat. No.6,119,472 which is a continuation-in-part of U.S. patent applicationSer. No. 09/083,340, filed by Ross on May 22, 1998, which is acontinuation-in-part of U.S. Ser. No. 08/869,040, filed Jun. 4, 1997,now U.S. Pat. No. 5,755,106, which was a continuation of U.S. Ser. No.08/602,302, filed Feb. 16, 1996, abandoned.

FIELD OF THE INVENTION

[0002] The present invention relates to refrigeration or coolingsystems. More particularly, the present invention relates to anevaporator design for refrigeration or cooling system.

BACKGROUND OF THE INVENTION

[0003] Ice cream or frozen custard machines, as well as other systemsfor cooling or freezing food stuffs, condiments, or other materials,typically include an evaporator situated proximate the material beingchilled. For example, in ice cream machines, liquid ice cream (e.g., themix) is typically inserted in a freezing chamber or barrel associatedwith the evaporator and is removed from the barrel as solid orsemi-solid ice cream. The evaporator removes heat from the freezingchamber as a liquid refrigerant, such as, FREON®, ammonia, R-404a, HP62,or other liquid having a low boiling point, changes to vapor in responseto the heat from the liquid ice cream. Typically, the evaporator ispartially filled with vapor as the liquid refrigerant boils (e.g.,becomes vapor) in the evaporator.

[0004] Since most heat transfer occurs when the liquid refrigerant ischanged to vapor, the partially filled evaporator is less efficient thana flooded evaporator (e.g., an evaporator filled entirely with liquidrefrigerant). The partially filled evaporator also tends to unevenlycool the ice cream because the parts of the evaporator which are filledwith vapor are not able to cool as effectively as the parts of theevaporator filled with liquid. Further, prior art ice cream machines aredisadvantageous because the temperature does not remain constant in theevaporator due to the accumulation of vapor. The inefficienciesresulting from the partially filled evaporator require a larger, moreexpensive, and less energy-efficient compressor. The goal of anefficient evaporator is to reduce the quantity of vapor in the barrel tooptimize the surface area for liquid refrigerant evaporation. Althoughthere is always a quantity of vaporized refrigerant in the barrel it isessential to minimize stagnation of the vapor within the heat exchangearea. By reducing the stagnation of the vaporized refrigerant within thebarrel, there is a more efficient transfer of heat. There can be acloser relationship of refrigerant evaporating temperature to ice creamor frozen custard freezing temperature. A result of this closertemperature difference is higher compressor efficiency.

[0005] In addition, custard or ice cream quality and efficientmanufacture of such custard or ice cream are dependent upon maintaininga constant evaporator temperature (e.g., constant barrel temperature).The barrel temperature must be kept in a proper range for making custardor ice cream so the custard or ice cream. If the custard or ice cream isallowed to become too cold, the mix or liquid ice cream in theevaporator becomes highly viscous and can block the travel of the icecream through the barrel. Blockage of the barrel in the freezing processis commonly known as “freeze up”.

[0006] Maintaining the temperature of the barrel at a constant level isparticularly difficult, as ice cream flow rates through the machine varyand change the cooling load on the evaporator. For example, more heatdissipation is required as more ice cream is produced (i.e., the flowrate is increased). Additionally, if the barrel temperature is too low,refrigerant flood-back problems can adversely affect the operation ofthe compressor. For example, if the refrigerant is not fully evaporatedas it reaches the compressor, the liquid refrigerant can damage thecompressor.

[0007] Heretofore, conventional systems allow refrigerant to travelfreely through the evaporator. Such a scheme can permit the refrigerantto travel through the evaporator without passing across the entiresurface area associated with the cooling chamber. For example, liquidrefrigerant can progress along a path of least resistance from theevaporator input to the evaporator output. This path of least resistancemay not cross the entire surface of the cooling chamber and can includepockets of trapped vapor. Accordingly, the freezing operation within thecooling chamber can be uneven, thereby resulting in an inefficientfreezing operation and a lower quality of custard or ice cream.

[0008] The vertical baffle system is made up of long, vertical bafflechambers. Certain conventional evaporators have utilized a verticalbaffling system to distribute the flow of refrigerant. However, vaporrefrigerant can accumulate near the top of each individual bafflechamber. This accumulation of refrigerant can cause uneven cooling inthe refrigeration chamber.

[0009] Thus, there is a need for an ice cream machine with a moreefficient evaporation. Further still, there is a need for a processwhich can more efficiently and more evenly cool ice cream or custard.Even further still, there is a need for a frozen custard machine whichutilizes a single barrel and yet produces high quality or premiumcustard and ice cream more quickly. Yet even further still, there is aneed for an evaporator within which refrigerant flows evenly across thesurface area of the cooling chamber.

SUMMARY OF THE INVENTION

[0010] An exemplary embodiment relates to an ice cream making system.The ice cream making system includes an evaporator, a compressor, and acondenser. The evaporator has a refrigerant input and a refrigerantoutput, and the compressor has a compressor input and a compressoroutput. The condenser has a condenser input and a condenser output. Theevaporator has an exterior surface and an interior surface. The interiorsurface defines a cooling chamber which has an ice cream input and anice cream output. The exterior surface and the interior surface definean evaporator chamber. The evaporator chamber may include a relativelyhorizontal baffle system between the refrigerant input and therefrigerant output. The compressor input is coupled to the refrigerantoutput. The condenser input is coupled to the compressor output and thecondenser output is coupled to the refrigerant input.

[0011] Another exemplary embodiment relates to a frozen custard makingsystem. The frozen custard making system includes a compressor having acompressor input and a compressor output, a condenser having a condenserinput and a condenser output, and an evaporator system having anevaporator input and an evaporator output. The evaporator system has aninterior surface defining a cooling chamber for chilling a custardproduct. The evaporator system can include a horizontal baffle systembetween the evaporator input and the evaporator output. The liquidrefrigerant substantially covers the cooling chamber. The condenserinput is coupled to the compressor output and the condenser output iscoupled to the evaporator input. The evaporator output is coupled to thecompressor input.

[0012] Still another embodiment relates to an ice cream freezingmachine. The ice cream freezing machine includes an evaporator having arefrigerant input and a refrigerant output, a compressor having acompressor input and a compressor output, and a condenser having acondenser input and a condenser output. The condenser input is coupledto the compressor output and the condenser output is coupled to therefrigerant input. The compressor input is coupled to the refrigerantoutput. A refrigerant travels from condenser through the evaporator tothe compressor. The evaporator has an interior surface defining aninterior cooling chamber. The evaporator includes an auxiliaryevaporator. The auxiliary evaporator avoids accumulation of vapor in theevaporator in an area by the cooling chamber. The evaporator includes abaffle system disposed adjacent the interior cooling chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The invention will hereafter be described with reference to theaccompanying drawings, wherein like reference numerals denote likeelements, and:

[0014]FIG. 1 is a schematic diagram illustrating an advantageous icecream machine;

[0015]FIG. 2 is a more detailed side view schematic diagram of thecylindrical cooling tank and auxiliary tank illustrated in FIG. 1;

[0016]FIG. 3 is a cross-sectional view of the cylindrical cooling tankillustrated in FIG. 2 at line 3-3;

[0017]FIG. 4 is a cross-sectional view of an alternative evaporator foruse in a system similar to the system illustrated in FIG. 1;

[0018]FIG. 5 is yet another cross-sectional view of an alternativeevaporator for use in a system similar to the system illustrated in FIG.1;

[0019]FIG. 6 is yet another cross-sectional view of an alternativeevaporator for use in a system similar to the system illustrated in FIG.1;

[0020]FIG. 7 is still another cross-sectional view of an alternativeevaporator for use in a system similar to the system illustrated in FIG.1; and

[0021]FIG. 8 is a schematic block diagram of an ice cream machine inaccordance with an exemplary embodiment of the present invention;

[0022]FIG. 9 is a schematic block diagram of yet another ice creammachine in accordance with another exemplary embodiment of the presentinvention;

[0023]FIG. 10 is cross sectional view of still another alternativeevaporator for use in a system similar to the system illustrated in FIG.1;

[0024]FIG. 11 is a schematic block diagram showing a batch freezingsystem in accordance with an exemplary embodiment;

[0025]FIG. 12 is a more detailed schematic block diagram showing thebatch freezing system illustrated in FIG. 11;

[0026]FIG. 13 is a flow diagram of a batch process for use with thebatch freezing system illustrated in FIG. 11;

[0027]FIG. 14 is a top view of an alternative evaporator for the icecream machine illustrated in FIG. 1, the evaporator includes baffles inaccordance with an exemplary embodiment; and

[0028]FIG. 15 is an exposed side view of the evaporator illustrated inFIG. 14, the exposed side view reveals the baffles within theevaporator.

DETAILED DESCRIPTION OF THE PREFERRED EXEMPLARY EMBODIMENT OF THEPRESENT INVENTION

[0029] A cooling system or ice cream machine 10 is diagrammaticallyshown in FIG. 1. Ice cream machine 10 includes an evaporator 20, anexpansion device 22, such as, a valve, a shut-off device 24, such as, asolenoid valve, a sight glass 26, a filter 28, a condenser 30, acompressor 32, an accumulator 34, and a valve 36. Evaporator 20 includesa cylindrical cooling tank 38 and an auxiliary tank 48. Machine 10 canbe manufactured without glass 26, valve 36, or device 24, or accumulator34.

[0030] Cylindrical cooling tank 38 includes a refrigerant input 40, arefrigerant output 42, a liquid ice cream input 44, and a solid icecream output 46. Auxiliary tank 48 includes a liquid refrigerant input52 and a vapor refrigerant output 54. Cylindrical cooling tank 38includes a cooling chamber 56 defined by an interior surface, wall, ortube 57 (FIG. 3) of tank 38.

[0031] Auxiliary tank 48 is positioned above with respect to gravity orover cylindrical cooling tank 38. Additionally, liquid refrigerant input52 is located above refrigerant output 42, and refrigerant input 40 oftank 38 is located beneath refrigerant output 42 of tank 38. Vaporrefrigerant output 54 of tank 48 is located above liquid refrigerantinput 52 of tank 48.

[0032] With reference to FIGS. 2 and 3, a shell or wall 58 ofcylindrical cooling tank 38 is manufactured from an outside tube 59having an inside diameter of 4.5 inches, an outside diameter of 4.75inches, and a length of 27.75 inches, and an inner tube 57 having aninside diameter of 3.75 inches, an outside diameter of 4.0 inches, and alength of 30 inches. For batch freezing embodiments described below withreference to FIGS. 11-13, the volume of tank 38 can be larger dependingon the desired yield. Alternatively, the distance between the outerdiameter of tube 57 and the inner diameter of tube 59 can be reduced to0.25 inches to increase surface velocities. Preferably, wall 58 is 0.125inches thick. The volume of interior cooling chamber 56 is approximately377 cubic inches. The volume of an evaporator chamber 61 between outertube 59 and inner tube 57 is approximately 92.6 cubic inches. Auxiliarytank 48 is preferably a piece of tubing or other container having alength of 12 inches, a width of 3 inches, and a depth of 2 inches. Theapproximate volume of tank 48 is 72 cubic inches. The various sizesdiscussed above can be proportionally adjusted in accordance with designcriteria.

[0033] The operation of ice cream machine 10 is described below withreference to FIGS. 1-3. Compressor 32 provides high pressure vaporrefrigerant to condenser 30. Ice cream machine 10 may utilize arefrigerant, such as, ammonia, FREON®, HP62, or other substance having alow boiling point. The type of refrigerant is not a limiting factor withrespect to the present invention.

[0034] Condenser 30 provides high pressure liquid refrigerant throughfilter 28, sight glass 26, and shut-off device 24 to expansion device22. Expansion device 22 provides low pressure liquid refrigerant toevaporator 20. More particularly, low pressure liquid refrigerant isprovided to refrigerant input 40 of cylindrical cooling tank 38. The lowpressure liquid refrigerant in cooling tank 38 is boiled, due to theheat from cooling chamber 56, refrigerant will start vaporizing withinthe barrel which accumulates in auxiliary tank 48. The low pressureliquid refrigerant in cylindrical cooling tank 38 preferably cools orfreezes the liquid ice cream received from input 44 in cooling chamber56. Although ice cream is disclosed, other food stuffs, substances, orcondiments may be utilized in machine 10.

[0035] More particularly, the warmer liquid ice cream with respect tothe liquid refrigerant provided to liquid ice cream input 44 is cooledand provided as frozen ice cream at ice cream output 46, as the lowpressure liquid refrigerant is transformed from liquid to vapor. The lowpressure vapor refrigerant collects via auxiliary tank 48. Preferably,system 10 is provided with enough liquid refrigerant so that all ofcylindrical cooling tank 38 is liquid vapor mix filling barrel andauxiliary tank 48 is two-thirds to one-half filled with liquidrefrigerant during normal operation of ice cream machine 10, the topone-third filled with vapor only.

[0036] The low pressure vapor refrigerant in tank 48 travels from vaporrefrigerant output 54 through valve 36 and accumulator 34 to compressor32. Compressor 32 changes the low pressure vapor refrigerant to highpressure vapor refrigerant and provides the high pressure vaporrefrigerant to condenser 30. Condenser 30 changes the high pressurevapor refrigerant to high pressure liquid refrigerant, which is providedto device 22.

[0037] The flooding of tank 38 advantageously provides even cooling asliquid ice cream travels from ice cream input 44 to ice cream output 46because the temperature and pressure of the low pressure liquidrefrigerant in cylindrical cooling tank 38 is maintained constant.Therefore, the ice cream in cooling chamber 56 is chilled evenlywherever it is vertically located within cooling chamber 56. Prior artcooling tanks tended to chill the ice cream unevenly near the top of theevaporator because liquid refrigerant was only located on the bottom ofthe evaporator because unsaturated vapor tends to stratify on top of theevaporator.

[0038] The use of such an advantageous evaporator 20 allows system 10 tobe designed with a relatively small compressor 32. The small size ofcompressor 32 makes ice cream machine 10 less expensive and moreenergy-efficient. Preferably, auxiliary tank 48 may be a coil of coppertubing located above cylindrical cooling tank 38. Preferably, auxiliarytank 48 is a tank located above cylindrical cooling tank 38, such as, acylindrical or spherical tank, reservoir, can, or other container.Cylindrical cooling tank 38 preferably has almost three times the volumeof auxiliary tank 48.

[0039] With reference to FIGS. 4-7, alternative embodiments for anadvantageous evaporator 20 are described as follows. The embodiments ofevaporator 20 shown in FIGS. 4-7 replace evaporator 20 in system 10described with reference to FIG. 1, wherein like numerals denote likeelements. However, the various dimensions given with respect to FIG. 1can be adjusted and modified in accordance with the operationalprinciples of the present invention. Evaporators 20 shown in FIGS. 4-7advantageously do not include a separate auxiliary evaporator, such as,auxiliary tank 48 shown in FIG. 1. Instead, evaporators 20 areadvantageously shaped so that cooling chamber 56 is completelysurrounded by liquid refrigerant as vapor accumulates above chamber 56(e.g., at the top of evaporator 20).

[0040] With reference to FIG. 4, evaporator 20 includes a first portion77 that collects vapor refrigerant and a second portion 79 that containsliquid refrigerant and completely surrounds cooling chamber 56. Firstportion 77 is above second portion 79 with respect to gravity.Evaporator 20 in FIG. 4 is configured by lowering inside tube 57 withrespect to outside tube 59 (e.g., inside tube 57 is not concentric withoutside tube 59). Tube 59 can be adjusted to be larger to ensure thatliquid refrigerant completely surrounds inner tube 57. Refrigerantoutput 42 is located above refrigerant input 40 with respect to gravity.

[0041] With reference to FIG. 5, tube 57 is provided in an outer section75. Outer section 75 has a rectangular cross-sectional area instead ofthe circular cross section of tube 59 (FIG. 3). Outer section 75 has asubstantially greater height than tube 57 to ensure that second portion79 can completely contain tube 57. In this way, cooling chamber 56 iscompletely surrounded by liquid refrigerant.

[0042] In FIG. 6, outer tube 59 includes a rectangular section 83provided at the top of outer tube 59. Rectangular chamber 83 replacesauxiliary tank 48 with reference to FIGS. 1-3. Vapor refrigerant isaccumulated in first portion 77 associated with rectangular chamber 83,and second portion 79 has liquid refrigerant which completely surroundscooling chamber 56.

[0043] With respect to FIG. 7, evaporator 20 is similar to evaporator 20discussed with reference to FIG. 6. However, a spherical or cylindricalchamber 85 is provide at a top of outer tube 59. Chamber 85 operatessimilarly to chamber 83, discussed with reference to FIG. 6.

[0044] With reference to FIG. 8, an ice cream machine or frozen custardmaking machine 100 is schematically shown including a remote section 110and an evaporator section 112. Remote section 110 can be physicallyapart from section 112. Preferably, evaporator section 112 is locatedinside an ice cream machine building or custard stand, and remotesection 110 is located external to the ice cream machine building.

[0045] Remote section 110 includes an accumulator 120, a valve 122, acompressor 124, a pressure switch 126, a condenser 128, a pressurecontrol valve 130, a remote condensing unit 132, and a valve 134. Valves122 and 134 are preferably manually actuated shut-off valves. Pressureswitch 126 is in parallel with compressor 124 and coupled between valve122 and condenser 128. Switch 126 provides a safety sensing point toshut the compressor off if too high or low a pressure condition exists.

[0046] For example, switch 126 can be configured to open whenrefrigerant pressure from valve 122 is greater than 325 pounds persquare inch gauge (PSIG) or when the pressure of the refrigerant fromvalve 122 is approximately 0 pounds PSIG. Switch 122 protects compressor124 and machine 100 from refrigerant overpressure and underpressure.Settings will vary with refrigerant type used and components selected.

[0047] Evaporator section 112 includes evaporator 220, accumulator/heatexchanger 222, sight glass 226, automatic expansion valve 232, liquidsolenoid 234, and filter/dryer 136. Temperature sensor 152 can beadjacent to a barrel or interior chamber for freezing ice creamassociated with evaporator 220. Evaporator 220 can be similar toevaporators discussed with reference to FIGS. 1-7. Alternatively,evaporator 220 can be a conventional evaporator barrel.

[0048] Compressor 124 is controlled by a control circuit 150 that iscoupled to a temperature sensor 152. Control circuit 150 turnscompressor 124 and a lamp 129 on and off in response to a temperaturesignal from sensor 152. Sensor 152 is preferably positioned to sense icecream, refrigerant, or other temperature associated with evaporator 220.Control circuit 150 preferably includes relay switches which providepower to lamp 129 and to compressor 124.

[0049] Compressor 124 provides vapor refrigerant through condenser 128to valve 130. Valve 130 is preferably a constant head pressure controlvalve. A hot gas bypass path 154 is located in parallel with condenser128 between compressor 124 and valve 130. Valve 130 receives liquidrefrigerant from condenser 128 and provides liquid refrigerant to remotecondensing unit 132. Remote condensing unit 132 is preferably anair-cooled condenser unit or alternately water cooled.

[0050] Valve 130 manipulates refrigerant flow, sending it either throughbypass path 154 or to condensing unit 132. Preferably, valve 130provides refrigerant at a constant pressure depending on refrigerantused to unit 132. Valve 130 can be a pressure actuated valvemanufactured by Sporlan Valve Company. Valve 130 automatically togglesversus pressure and spring tension.

[0051] Condensing unit 132 is a receiver tank mounted on condenser 128.The refrigerant preferably accumulates as a liquid (e.g., puddles up) inunit 132. Liquid refrigerant is provided through valve 134- to afilter/dryer 136.

[0052] Filter dryer 136 absorbs moisture, acids, chips, and debris fromthe liquid refrigerant provided through valve 134. Liquid refrigeranttravels through solenoid 234, which operates as an electricallycontrolled on and off valve (solenoid can be on inlet or outlet ofevaporator). The liquid refrigerant is provided through accumulator/heatexchanger 222 to sight glass 226.

[0053] Accumulator/heat exchanger 222 is preferably manufactured byRefrigeration Research, Inc. and includes an input 242, an output 244,an input 248, and an output 252. Input 242 is coupled to solenoid 234and to an internal path 254 that is coupled to output 244. Path 254wraps around a path 260 coupled between input 258 and output 252.

[0054] Path 260 is preferably an eight-inch diameter, 24-inch highcylindrical enclosure. Path 260 has an opening 264 coupled to output252. Opening 264 is located near a top end of path 260.

[0055] Liquid refrigerant from output 244 is provided through site glass226 to automatic expansion valve 232. Automatic expansion valve 232 ispressure actuated in response to downstream pressure (pressure fromevaporator 220). Valve 232 is different than conventional expansionvalve 22 discussed with reference to FIG. 1. Expansion valve 22 is atemperature expansion valve that provides more refrigerant flow inresponse to temperature increases and less refrigerant flow in responseto temperature decreases. In contrast, automatic expansion valve 232provides liquid refrigerant in response to pressure. In bath freezingapplications described below with reference to FIGS. 11-13, expansionvalve 22 can be an automatic thermostatic expansion valve. When thedownstream pressure is low, more refrigerant is provided by valve 232.When the downstream pressure is high, less pressure is provided by valve232. In this way, valve 232 is a metering device which senses pressurein evaporator 220 and maintains pressure in evaporator 220 at aconsistent level.

[0056] Valve 232 can be spring-actuated and is preferably set tomaintain the refrigerant in evaporator 220 at a constant 31 PSIGpressure level (approximately 0° Fahrenheit). Settings will vary withrefrigerant type used and components selected. The use of expansionvalve 232 allows machine 100 to achieve superior performance as loads onevaporator 220 change. For example, as rates of mix in evaporator 220change, temperature of the barrel in evaporator 220 can fluctuate ifvalve 232 is not present. Valve 232 maintains the pressure ofrefrigerant constant in evaporator 220, and, hence, the temperatureconstant in evaporator 220.

[0057] Vapor refrigerant or liquid and vapor refrigerant is providedfrom evaporator 220 to input 248 of accumulator/heat exchanger 222.Liquid refrigerant falls to the bottom of path 260, while vaporrefrigerant escapes through opening 264 to output 252. In this way,refrigerant along path 254 is cooled by the liquid refrigerant in path260. This cooling process also heats the liquid refrigerant in path 260which then is provided as vapor through opening 264. Liquid refrigerantis prevented from reaching the optical accumulator 120 as liquidrefrigerant is boiled off and provided as vapor. Therefore,accumulator/heat exchanger 222 provides both efficiency and safety byprotecting compressor 124 from receiving liquid refrigerant.

[0058] Vapor refrigerant from output 252 is provided to accumulator 120,which provides vapor through valve 122 to compressor 124. Connectionsbetween evaporator 220, accumulator/heat exchanger 222, accumulator 120,and compressor 124 are sized for refrigeration capacity levels typically{fraction (7/8)}-inch copper tubing. Connections between compressor 124,valve 130, unit 132, valve 134, filter 136, solenoid 234, and input 242are sized for capacity levels typically {fraction (3/8)}-inch coppertubing. Additionally, connections between output 244, sight glass 226,expansion valve 232 and evaporator 220 are sized for capacity levelstypically {fraction (3/8)} inch copper tubing. Path 254 is preferably{fraction (3/8)}-inch copper tubing. Alternatively, valves can be addedto manipulate temperatures and pressures to assist ice cream expulsionfrom the barrel (e.g. machine 100).

[0059] Control circuit 150 and temperature sensor 152 provide twocontrol functions, a hold mode and a monitor mode, for machine 100. Theoperator initiates the mode, when machine 100 is turned off with custardor ice cream within the barrel of evaporator 220. To avoid bacterialgrowth in the custard mix within the barrel and to improve initialstarting speed, a hold mode is installed. In the hold mode, controlcircuit 150 monitors the temperature of evaporator 220 via sensor 152and, when a temperature is reached in which the ice cream begins to melt(approximately 28 degrees), control circuit 150 turns on compressor 124,and machine 100 begins cooling the ice cream. Once the temperature ofthe ice cream falls below a certain temperature, such as, 27 degreesFarenheit, control circuit 150 turns off compressor 124. Temperaturesensor 152 can monitor the temperature of refrigerant travelling toinput 248, the temperature of the ice cream, and the temperature of aninterior or exterior chamber of evaporator 220 to ascertain thetemperature in the barrel.

[0060] In the monitor mode, control circuit 150 monitors the temperatureassociated with evaporator 220. If the temperature is too low (allrefrigerant is not being evaporated), machine 100 is operatinginefficiently, the barrel of evaporator 220 is empty (e.g., the icecream mix has run out), machine 100 is clogged, or some other change inthe mix or load on evaporator 220 has occurred. In such a case, controlcircuit 150 turns compressor 124 off and provides an indication to theoperator that the system should be checked. The indication can beprovided through lamp 129 or by an audio alarm. In this way, in themonitor mode, control circuit 150 can prevent freeze-ups in the barrelof evaporator 220.

[0061] The combination of automatic expansion valve 232 (or athermostatic expansion valve), heat exchanger 222, and control circuit150 advantageously makes the operation of machine 100 significantlyeasier. Efficient use of machine 100 is almost guaranteed due to theconstant pressure provided by valve 232, the boiling of liquidrefrigerant in path 260 by accumulator/heat exchanger 222, and thetemperature control by control circuit 150. With such a system, theapplicant has observed significantly increased simplicity of operatingmachine 100. The efficiency can be augmented by utilizing an evaporator220 similar to evaporators discussed with reference to FIGS. 1-7.

[0062] With reference to FIG. 9, an ice cream or frozen custard makingmachine 300 is schematically shown. Machine 300 is substantially similarto machine 100 described with reference to FIG. 8 wherein like numeralsdenote like elements. System 300 includes a crankcase regulator 302, acrankcase regulator 304, and a suction solenoid 308. Solenoid 308 iscoupled between output 252 of heat exchanger 222 and accumulator 120.Solenoid 302 prevents liquid refrigerant from reaching compressor 124during maintenance, shutdown or other procedures.

[0063] Switch 126 is configured to open at low pressures i.e., 5 PSIGand close or reset at pressures of 20 PSIG. Regulator 304 is set to apressure of 235 PSIG. Regulator 302 is set to a pressure ofapproximately 25 PSIG. Expansion valve 232 is set to a pressure ofapproximately 35 PSIG. (If a thermostatic expansion valve is used, thevalve is not set to a pressure.) Settings will vary with refrigeranttype used and components selected. Regulators 302 and 304 are preferablyspring loaded pressure regulators, such as, crankcase pressureregulating valves manufactured by Sporlan Valve Company. Regulators 302and 304 provide more predictable pressure of refrigerant in machine 300.Machine 300 can include a control circuit 150 and temperature sensor 152(FIG. 8).

[0064] With reference to FIG. 10, yet another alternative embodiment foran evaporator for an ice cream custard machine is shown. In FIG. 10, anevaporator barrel 320 which includes a custard barrel 322 with arefrigerant input 324 and an accumulator 326 which includes arefrigerant output 328. Refrigerant input 324 is located belowaccumulator 326 and refrigerant output 328 with respect to gravity.Liquid ice cream or custard enters barrel 322 and leaves barrel 322 asfrozen custard. The liquid ice cream is cooled by refrigerant travelingbetween input 324 and output 328. Accumulator 326 operates as anauxiliary evaporator or auxiliary tank similar to tank 48 discussed withreference to FIG. 1. Accumulator 326 is preferably tilted slightlyupward with respect to gravity and is shaped as shown in FIG. 10 toreduce space requirements. Accumulator 326 is higher at the end withoutput 328. Preferably, refrigerant output 328 is connected on a topside of accumulator 326. Evaporator 330 can be utilized in machine 200or machine 300 described with reference to FIGS. 8 and 9.

[0065] In FIG. 11, a batch freezing system or bulk ice cream makingsystem 1000 includes an evaporator system 1002 and a cabinet freezer1004. Evaporator system 1002 can be similar to any of the evaporatorsdiscussed with reference to FIGS. 1-10. Preferably, evaporator system1002 is a flooded evaporator system including an evaporator barreldefining an evaporator chamber 1004 and a cooling chamber 1006.

[0066] Cooling chamber 1006 is defined by interior walls, and evaporatorchamber 1004 is defined by cooling chamber 1006 and exterior walls.Cooling chamber 1006 includes an ice cream input 1010 and an ice creamoutput 1020. A mix of ice cream or custard is provided to ice creaminput 1010 and chilled in cooling chamber 1006. Cooling chamber 1006 caninclude an auger 1012 which mixes the mix in cooling chamber 1006. Inaddition, auger 1012 can be utilized to transport the mix from an end ofchamber 1006 associated with input 1010 to an end of chamber 1006associated with output 1020. Preferably, auger 1012 is driven by a motoror other device and the mix remains in cooling chamber 1006 until itreaches an appropriate consistency.

[0067] The mix remains in chamber 1006 until it reaches a “slurry” formor texture which typically occurs at temperatures of 22° F. Once theslurry form is reached, the mix exits output 1020 and is placed into acontainer 1030. A number of means can be utilized to determine when themix is in slurry form. For example, the consistency or texture of themix in cooling chamber 1006 can be electronically monitored. In anotherscheme, the temperature of the mix can be monitored via temperaturesensors. In another alternative, operator observation can determine whenthe mix is a slurry form.

[0068] Once container 1030 is filled, it is placed in cabinet freezer1004. The cabinet freezer can be any type of cooling system. Preferably,the cabinet freezer is operated between temperatures 22° F. to −5° F.(most preferably, cabinet freezer is set to −20° F. to bring the icecream temperature to −5° F.). Once container 1030 is in cabinet freezer1004, the mix in slurry form is allowed to ripen to become theappropriate temperature for ice cream.

[0069] Evaporator system 1002 has significant advantages overconventional evaporation systems utilized in batch freezers. Theconventional evaporator system utilized in the batch freezer typicallyutilize a barrel surrounded by copper tubes. In contrast, as discussedwith reference to FIG. 11, system 1000 utilizes an evaporator systemhaving a flooded evaporator in which liquid refrigerant surroundscooling chamber 1006. The various designs described with reference toFIGS. 1-10 can be utilized for such an evaporator system. The use ofsuch an evaporator system cools the mix faster which increases theefficiency of the system and makes ice cream products with smaller icecrystals. The smaller ice crystals provide a smoother texture orconsistency for the product. Customers prefer a smooth consistency forice cream and custard products. Generally, the mix can react slurry formin less than ten minutes.

[0070] With reference to FIG. 12, system 1000, is shown in more detail.Evaporator system 1002 includes an auxiliary evaporator 1100 and abarrel and a barrel evaporator 1102. The system 1002 also includes acompressor 1108, a condenser 1110, a control circuit 1112, and a motor1114. The condenser 1110 has an output coupled to an input of evaporator1102 and compressor 1108 has an input coupled to an output of auxiliaryevaporator 1100. Condenser 1110 has an input coupled to an output ofcompressor 1108.

[0071] Evaporator 1102 can include a 10.75 inch inner diameter outertube 1007 and a 10 inch inner diameter inner tube 1009. The wall of tube1009 is 0.125 inches thick, and the wall of tube 1007 is 0.25 inchesthick. Tube 1009 is preferably 20 inches long, and tube 1007 ispreferably 18 inches long. According to another embodiment, compressor1108 can be coupled to a top of the right side (non-pointed side in FIG.12) of evaporator 1100 and a bottom of left side can be coupled to thebottom of the left side of evaporator 1100.

[0072] A control circuit 1112 is electrically coupled to motor 1114 andto a gate 1130. Gate 1130 is mechanically coupled to ice cream output1020. Motor 1114 drives auger 1012. As the texture or consistency of themix in coolant chamber 1006 increases, motor 1114 requires more currentto turn at the same speed. Control circuit 1112 monitors the current tomotor 1114 and opens gate 1130 when the current indicates that the mixhas reached a desired consistency. The use of measuring amperage througha motor to determine ice cream consistency has been utilized inconventional ice cream makers. Control circuit 1112 can automaticallyprovide an indication that the consistency has been reached andautomatically open gate 1130.

[0073] Upon opening gate 1130, the mix which is in slurry form enterscontainer 1030. Container 1030 can be automatically placed or manuallyplaced in freezer 1004 for ripening.

[0074] With reference to FIGS. 12 and 13, a process for manufacturingice cream includes placing a mix in an interior cooling chamber 1006 ata step 1202. At a step 1204, auger 1012 is utilized to stir the mix incooling chamber 1006. Preferably, the mix is cooled in a floodedevaporator such as evaporator system 1002. Once the mix reaches atexture or consistency associated with a slurry form (e.g. inapproximately less than 10 minutes and at a temperature 22° F.), the mixis removed and placed in a container 1030, such as, a bucket. Gate 1130can be automatically opened in a step 1206 to allow the mix in slurryform to accumulate in container 1030. Generally, auger 1012 can beutilized to push the mix out of output 1020 when gate 1130 is opened. Ata step 1208, container 1030 is transferred to freezer 1004 eitherautomatically or manually for ripening. Generally, ripening occurs at atemperature between 22° F. to −5° F. Most preferably, the cabinetfreezer set to −20° F. to bring the ice cream to a temperature of −5° F.

[0075] With reference to FIGS. 14 and 15, an evaporator system 2000 canbe utilized in system 1000 discussed with reference to FIGS. 12 and 13or any of the evaporators discussed with reference to FIGS. 1-11.Evaporator system 2000 includes a main evaporator 2007 and an auxiliaryevaporator 2008. Main evaporator 2007 includes an exterior wall 2020 andan interior wall 2022.

[0076] Interior wall 2022 defines an interior cooling chamber 2014 whichhas an ice cream input and an ice cream output. Cooling chamber 2014 ispreferably defined by an inner tube 2023 having an inner diameter of 3¾inches and an outer diameter of 4 inches. Inner tube 2023 is preferablystainless steel.

[0077] Wall 2020 can be formed from an outer tube 2025. Outer tube 2025is preferably stainless steel tube and has an inner diameter of 4½inches and an outer diameter of 4{fraction (3/4 )} inches. The spacebetween tubes 2025 and 2023 defines an evaporator chamber 2030.

[0078] Advantageously, evaporator 2007 includes a baffle system 2032disposed within evaporator chamber 2030. Baffle system 2032 preferablyincludes relatively horizontal walls or baffles. The walls are generallyparallel. A pair of walls in baffle system 2032 define a relativelyhorizontal baffle chamber. The term “relatively horizontal” refers tothe disposition of an object in a more horizontal fashion than avertical fashion.

[0079] Baffle system 2032 defines at least one pathway from anevaporator input 2002 to an evaporator output 2016 which causesrefrigerant to travel in a significantly larger horizontal fashion thana vertical fashion. The pathway is preferably labyrinthian, havingopenings from one chamber to the next at opposite ends. The openingspreferably have an area of approximately 0.75 square inches. The chamberdimensions can have a cross-sectional area ranging from 0.5 to 1.0square inches (preferably 0.5 square inches). In this way, baffle system2032 can ensure that the entire surface area associated with coolingchamber 2014 (inner tube 2023) is chilled evenly. The chamber dimensionscan change with then placement along the cylindrical walls 2020 and2022.

[0080] The walls associated with baffle system 2032 can be 0.055 to0.125 inches (e.g., 20 gauge material) thick of stainless steel walls.Preferably, the walls define a relatively leakproof pathway fromevaporator input 2002 to evaporator output 2016. Auxiliary evaporator2008 does not include a baffle system.

[0081] Auxiliary evaporator 2008 works similar to the auxiliaryevaporators discussed with reference to FIGS. 1-11 (tank 48, chambers 83and 85, auxiliary evaporator 1100, accumulator 326, etc.). Auxiliaryevaporator 2008 can be in a variety of shapes or forms as discussedabove. Auxiliary evaporator includes an output 2004.

[0082] The term “coupled”, as used in the present application, does notnecessarily mean directly attached or connected. Rather, the term“coupled” in the present application means in fluid or electricalcommunication with. Two components may be coupled together throughintermediate devices. For example, the evaporator input is coupled tothe condenser output even though the expansion valve, accumulator/heatexchanger, and sight glass are situated between the evaporator input andthe condenser output.

[0083] It is understood that, while the detailed drawings and specificexamples given to describe the preferred exemplary embodiment of thepresent invention, they are for the purpose of illustration only. Theapparatus of the invention is not limited to the precise details andconditions disclosed. For example, although food stuffs and ice creamare mentioned, the invention may be utilized in a variety ofrefrigeration or cooling systems. Further, single lines for carryingliquid refrigerant can represent multiple tubes. Additionally, althougha particular valve, accumulator, compressor, condenser, and filterconfiguration is shown, the advantageous machine can be arranged inother configurations. Further still, the evaporator barrel and freezercan have any number of shapes, volumes, or sizes. Various changes can bemade to the details disclosed without departing from the spirit of theinvention, which is defined by the following claims.

What is claimed is:
 1. An ice cream making system, comprising: anevaporator having a refrigerant input and a refrigerant output, theevaporator having an exterior surface and an interior surface, theinterior surface defining a cooling chamber, the interior coolingchamber having an ice cream input and an ice cream output, the exteriorsurface and the interior surface defining an evaporator chamber, theevaporator chamber including a relatively horizontal baffle systembetween the refrigerant input and the refrigerant output; a compressorhaving a compressor input and a compressor output, the compressor inputbeing coupled to the refrigerant output; and a condenser having acondenser input and a condenser output, the condenser input beingcoupled to the compressor output and the condenser output being coupledto the refrigerant input.
 2. The ice cream making system of claim 1 ,wherein the evaporator includes an auxiliary evaporator means forminimizing accumulation of vapor around the interior chamber bycollecting refrigerant in a vapor form.
 3. The ice cream making systemof claim 1 , further comprising: an auger disposed in the interiorchamber; and a motor coupled to the auger, the motor driving the auger.4. The ice cream making system of claim 1 , wherein the baffle systemincludes thin stainless steel walls.
 5. The ice cream making system ofclaim 4 , wherein the baffle system defines a path, the path beingsignificantly longer in a horizontal direction than a verticaldirection.
 6. The ice making system of claim 5 , wherein the bafflesystem includes at least 6 (six) walls.
 7. The ice making system ofclaim 6 , wherein the path has a cross-sectional area of approximately0.5 square inches.
 8. A frozen custard making system, comprising: acompressor having a compressor input and a compressor output; acondenser having a condenser input and a condenser output, the condenserinput being coupled to the compressor output; and an evaporator systemhaving a evaporator input and an evaporator output, the condenser outputis coupled to the evaporator input, the evaporator output is coupled tothe condenser input, the evaporator system having an interior surfacedefining a cooling chamber for chilling a custard product, theevaporator system including a horizontal baffle system between theevaporator input and the evaporator output whereby liquid refrigerantsubstantially covers a surface area of the cooling chamber.
 9. Thefrozen custard making system of claim 8 , further comprising anauxiliary evaporator for collecting vapor refrigerant.
 10. The frozencustard making system of claim 9 , wherein the horizontal baffle systemevaporator is cylindrical.
 11. The frozen custard making system of claim10 , wherein the cooling chamber is cylindrical
 12. The frozen custardmaking system of claim 8 , further comprising: a temperature sensorcoupled to determine a temperature associated with the evaporator systemand to generate a temperature signal; and a control circuit coupled tothe temperature sensor, the control circuit providing indicia if thetemperature signal is below a threshold.
 13. The frozen custard makingsystem of claim 12 , wherein the indicia is illumination of a warninglight.
 14. The frozen custard making system of claim 8 , wherein theevaporator system is substantially filled with a liquid refrigerant,wherein the liquid refrigerant completely fills the evaporator in thearea by the cooling chamber and fills the auxiliary evaporator one-halfto two-thirds full.
 15. The frozen custard making system of claim 8 ,further comprising: an expansion valve having a valve input and a valveoutput, the valve input being coupled to the conveyor output, the valveoutput being coupled to the evaporator input.
 16. An ice cream freezingmachine, comprising: an evaporator having a refrigerant input and arefrigerant output, the evaporator having an interior surface definingan interior cooling chamber; wherein the evaporator includes anauxiliary evaporator, the auxiliary evaporator avoiding accumulationvapor in the evaporator in an area by the interior cooling chamber, theevaporation including a baffle system disposed adjacent the interiorcooling chamber; a compressor having a compressor input and a compressoroutput, the compressor input being coupled to the refrigerant output; acondenser having a condenser input coupled to the compressor output anda condenser output coupled to the refrigerant input; whereby arefrigerant travels from the condenser through the evaporator to thecompressor
 17. The custard freezing machine of claim 16 , wherein thebaffle system includes horizontal walls defining horizontal chambers.18. The custard freezing machine of claim 17 , wherein the horizontalchambers have a cross-sectional area of less than 1.0 square inches. 19.The custard freezing machine of claim 16 , further comprising: anexpansion valve having a valve input and a valve output, the valve inputbeing coupled to the refrigerant input.
 20. The custard freezing machineof claim 16 , wherein an accumulator/heat exchanger having a first inputcoupled to the condenser output, a first output coupled to the valveinput, the second input coupled to the evaporator output, and a secondoutput coupled to the compressor input